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package forwardcrd
import (
"context"
"errors"
"fmt"
"sync"
"time"
"github.com/coredns/coredns/plugin"
"github.com/coredns/coredns/plugin/dnstap"
"github.com/coredns/coredns/plugin/forward"
corednsv1alpha1 "github.com/coredns/coredns/plugin/forwardcrd/apis/coredns/v1alpha1"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
"k8s.io/apimachinery/pkg/runtime"
utilruntime "k8s.io/apimachinery/pkg/util/runtime"
"k8s.io/apimachinery/pkg/util/wait"
"k8s.io/apimachinery/pkg/watch"
"k8s.io/client-go/dynamic"
"k8s.io/client-go/tools/cache"
"k8s.io/client-go/util/workqueue"
)
const defaultResyncPeriod = 0
type forwardCRDController interface {
Run(threads int)
HasSynced() bool
Stop() error
}
type forwardCRDControl struct {
client dynamic.Interface
scheme *runtime.Scheme
forwardController cache.Controller
forwardLister cache.Store
workqueue workqueue.RateLimitingInterface
pluginMap *PluginInstanceMap
instancer pluginInstancer
tapPlugin *dnstap.Dnstap
namespace string
// stopLock is used to enforce only a single call to Stop is active.
// Needed because we allow stopping through an http endpoint and
// allowing concurrent stoppers leads to stack traces.
stopLock sync.Mutex
shutdown bool
stopCh chan struct{}
}
type lifecyclePluginHandler interface {
plugin.Handler
OnStartup() error
OnShutdown() error
}
type pluginInstancer func(forward.ForwardConfig) (lifecyclePluginHandler, error)
func newForwardCRDController(ctx context.Context, client dynamic.Interface, scheme *runtime.Scheme, namespace string, pluginMap *PluginInstanceMap, instancer pluginInstancer) forwardCRDController {
controller := forwardCRDControl{
client: client,
scheme: scheme,
stopCh: make(chan struct{}),
namespace: namespace,
pluginMap: pluginMap,
instancer: instancer,
workqueue: workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "ForwardCRD"),
}
controller.forwardLister, controller.forwardController = cache.NewInformer(
&cache.ListWatch{
ListFunc: func(options metav1.ListOptions) (runtime.Object, error) {
if namespace != "" {
return controller.client.Resource(corednsv1alpha1.GroupVersion.WithResource("forwards")).Namespace(namespace).List(ctx, options)
}
return controller.client.Resource(corednsv1alpha1.GroupVersion.WithResource("forwards")).List(ctx, options)
},
WatchFunc: func(options metav1.ListOptions) (watch.Interface, error) {
if namespace != "" {
return controller.client.Resource(corednsv1alpha1.GroupVersion.WithResource("forwards")).Namespace(namespace).Watch(ctx, options)
}
return controller.client.Resource(corednsv1alpha1.GroupVersion.WithResource("forwards")).Watch(ctx, options)
},
},
&unstructured.Unstructured{},
defaultResyncPeriod,
cache.ResourceEventHandlerFuncs{
AddFunc: func(obj interface{}) {
key, err := cache.MetaNamespaceKeyFunc(obj)
if err == nil {
controller.workqueue.Add(key)
}
},
UpdateFunc: func(oldObj, newObj interface{}) {
key, err := cache.MetaNamespaceKeyFunc(newObj)
if err == nil {
controller.workqueue.Add(key)
}
},
DeleteFunc: func(obj interface{}) {
key, err := cache.DeletionHandlingMetaNamespaceKeyFunc(obj)
if err == nil {
controller.workqueue.Add(key)
}
},
},
)
return &controller
}
// Run starts the controller. Threads is the number of workers that can process
// work on the workqueue in parallel.
func (d *forwardCRDControl) Run(threads int) {
defer utilruntime.HandleCrash()
defer d.workqueue.ShutDown()
go d.forwardController.Run(d.stopCh)
if !cache.WaitForCacheSync(d.stopCh, d.forwardController.HasSynced) {
utilruntime.HandleError(errors.New("Timed out waiting for caches to sync"))
return
}
for i := 0; i < threads; i++ {
go wait.Until(d.runWorker, time.Second, d.stopCh)
}
<-d.stopCh
// Shutdown all plugins
for _, plugin := range d.pluginMap.List() {
plugin.OnShutdown()
}
}
// HasSynced returns true once the controller has completed an initial resource
// listing.
func (d *forwardCRDControl) HasSynced() bool {
return d.forwardController.HasSynced()
}
// Stop stops the controller.
func (d *forwardCRDControl) Stop() error {
d.stopLock.Lock()
defer d.stopLock.Unlock()
// Only try draining the workqueue if we haven't already.
if !d.shutdown {
close(d.stopCh)
d.shutdown = true
return nil
}
return fmt.Errorf("shutdown already in progress")
}
func (d *forwardCRDControl) runWorker() {
for d.processNextItem() {
}
}
func (d *forwardCRDControl) processNextItem() bool {
key, quit := d.workqueue.Get()
if quit {
return false
}
defer d.workqueue.Done(key)
err := d.sync(key.(string))
if err != nil {
log.Errorf("Error syncing Forward %v: %v", key, err)
d.workqueue.AddRateLimited(key)
return true
}
d.workqueue.Forget(key)
return true
}
func (d *forwardCRDControl) sync(key string) error {
obj, exists, err := d.forwardLister.GetByKey(key)
if err != nil {
return err
}
if !exists {
plugin := d.pluginMap.Delete(key)
if plugin != nil {
plugin.OnShutdown()
}
} else {
f, err := d.convertToForward(obj.(runtime.Object))
if err != nil {
return err
}
forwardConfig := forward.ForwardConfig{
From: f.Spec.From,
To: f.Spec.To,
TapPlugin: d.tapPlugin,
}
plugin, err := d.instancer(forwardConfig)
if err != nil {
return err
}
err = plugin.OnStartup()
if err != nil {
return err
}
oldPlugin, updated := d.pluginMap.Upsert(key, f.Spec.From, plugin)
if updated {
oldPlugin.OnShutdown()
}
}
return nil
}
func (d *forwardCRDControl) convertToForward(obj runtime.Object) (*corednsv1alpha1.Forward, error) {
unstructured, ok := obj.(*unstructured.Unstructured)
if !ok {
return nil, fmt.Errorf("object was not Unstructured")
}
switch unstructured.GetKind() {
case "Forward":
forward := &corednsv1alpha1.Forward{}
err := d.scheme.Convert(unstructured, forward, nil)
return forward, err
default:
return nil, fmt.Errorf("unsupported object type: %T", unstructured)
}
}
|
